(a) Field of the Invention
The invention relates to novel compositions comprising a first polymer component comprising a poly(arylene ether ketone) and a second polymer component comprising a copolymer of tetrafluoroethylene.
(b) Background and Invention
Poly(arylene ether ketones) are linear thermoplastic polymers that exhibit excellent mechanical, physical, chemical and electrical properties, and are especially useful for their superior thermal properties. These polymers can be molded by conventional techniques into shaped articles for a wide variety of end uses. These polymers are ductile, machinable, self-extinguishing and relatively inert to most aqueous mineral acids. However, it has been found that poly(arylene ether ketones) exhibit crazing under certain conditions of strain induced by certain solvents and are stiff and relatively inflexible.
Copolymers of propylene and tetrafluoroethylene are known in the art. In U.S. Pat. No. 3,467,635 such copolymers are crosslinked with a curing agent such as a peroxide or an amine. In U.S. Pat. No. 3,718,558 copolymers are described which have been crosslinked using high energy ionizing radiation, such as an electron accelerator. High mechanical strength copolymers of propylene and tetrafluoroethylene are described in U.S. Pat. No. 3,825,510. Such polymers absorb mineral acids. Copolymers of tetrafluoroethylene and (hexafluoropropylene and vinylidene fluoride) are also known. These copolymers are recognized as appreciably different in properties from copolymers of vinylidine fluoride and hexafluoropropylene alone. See U.S. Pat. No. 3,306,879. These patents are incorporated herein by reference.
Poly(arylene ether ketones) and copolymers of propylene and tetrafluoroethylene have previously been independently mixed with other polymers. In U.S. Pat. No. 4,395,512 copolymers of propylene and tetrafluoroethylene are mixed with a polyphenylenesulfide. The mixtures exhibit improved impact resistance but do not exhibit reduced mineral acid absorption.
In U.S. Pat. No. 3,400,065 blends of poly(arylene ethers) with copolymers of vinylidene fluoride-hexafluoropropylene (Viton A from DuPont) are disclosed. It is reported that the poly(arylene ether) can be a poly(arylene ether ketone). However, only one poly(arylene ether ketone) is used in a working example and it is one which can be processed at relatively low temperatures. It has been found that poly(arylene ether ketones) requiring higher processing temperatures cannot be successfully blended with vinylidene fluoride-hexafluoropropylene copolymers.